Governing mechanism



Nov. 14, 1933. SCHMIDT 1,935,062.

GOVERNING MECHANISM Filed April 50', 1951 I t k I a u. m A t k n d ,l 2H0- Q r 0 MM H g n E z mu t a -5 a t 3 5 9 Ma In. 0 d 2 1 T 7 L INVENTORI H. F. 5CHM1DTZ a 4b. ATTORNEY Fae.

WITNESSES:

Patented Nov. 14, 1933 ATENT OFFICE V 1,935,062 GOVERNING MECHANISMHenry F. Schmidt, Lansdowne, Pa., assignor to Westinghouse Electric "&Manufacturing Cornpany, a corporation of Pennsylvania Application April30, 1931. Serial No. 534,053

. 7 Claims.

My invention relates to an operating mechanism for the maneuvering valveof a reversing turbine, and it has for its object to provide a combinedgoverning and 'maneuvering mechanism for operating, such maneuveringvalve.

Maneuvering valves of reversing turbines heretoiore have generally beenoperated manually. Such arrangement, in order to obtain rapid change ofspeed, required initial movement of w the valve to a position beyondthat corresponding to the speed desired and then a return movement tosaid corresponding position.

In accordance with my invention, I employ a -governor having speedchanger means, and preferably of the fluid pressure type, for each ofthe ahead and astern valves. I provide a mechanism for operating thespeed changer means of the governors, said mechanism being operative,upon movement in one direction, to successively decrease the setting ofone governor to zero speed setting and then to raise the setting of theother governor from zero speed setting.

This is preferably accomplished by providing a gear for operating eachspeed changer means and a controlling gear adapted to engage said gears,the controlling gear being movable into engagement with one or the otherof. said governor gears to vary the speed setting.

The above and other objects'are effected by my invention as will beapparent from the 01- lowing description and claims taken in connectionwith the accompanying drawing, forming a part of this application, inwhich;

Fig. 1 is an elevational view of a turbine; l

Fig. 2 is a vertical sectional view of the maneuvering valve andoperating mechanism iorthe' turbine of Fig. 1: a

Fig. 3 shows a detail 01' the. operating mechanism;

Fig. 4 is a plan view of the maneuvering valve and operating mechanismof Fig. 2; and,

Fig. 5 shows another detail of the operating mechanism.

Referring now to the drawing more in detail, I show a reversing turbine'10, which may be usedwherever motive power in opposite directions isrequired, particularly in marine propulsion, The turbine 10 has an aheadinlet 11, through which motive fluid is, admitted to the ahead sectionof the turbine for operation thereof in one direction, and an asterninlet 12,

through which motive fluid is admitted to the reversing astern sectionof the turbine effecting operation thereof in the opposite direction.

The motive fluid admission to the ahead inlet is controlled by an aheadadmission valve 15, and the motive fluid admission to the astern inletis controlled by an astern admission valve 16. The ahead and asternadmission valves communicate with the ahead and astern inlets,respectively, through suitable conduit means. The aggregate of the aheadand esteem admission valves is commonly known in the art as amaneuvering valve.

The valves 15-and' 16 are provided with governors 17 and 18,respectively. The governor 17 includes a cylinder 19, a piston 20 in thecylinder, and a piston rod 21 connecting the piston and the valve stem.As the rod 21 is rotatable, ball bearings are interposed in itsconnections 'with the piston and the valve stem, the latter connection,designated 22, being shown in detail in Fig. 3. A gear 23 is fixed onthe rod 21 for rotating the same. A spring nut 24 is screwthreaded, byleft-hand screw-threads 38, on the upper end of the rod 21. A spring 25has one end fastened to the spring nut 24 and its other end to aspring-holding member 26 fixed in the bottom of the cylinder 19.

The corresponding partsoi! the governor 18 are designated by the samereference numerals with the prime mark added. The governor 18 is similarto the governor 17, except that the screw threads 38' are right-handthreads and the gear 23' is diflerently disposed as will be furtherexplained.

Fluid pressure varying as the square of the speed of the turbine isdeveloped by an impeller 27 mounted on the turbine shaft 28. It iscommunicatedthrough a conduit 29 to the upper end of each cylinder, inwhich it biases the piston downwardly.

A controlling gear 30 is fixedly carried on a shaft 31, which isdisposed parallel to the rods 21 and in such position that the gear 30is adapted,

upon proper axial movement, to mesh with eithe shaft 38 for fluidpressure acting on the piston 20 moves the 18 at zero speed setting.

admission valve in closing direction to restrict further increase inspeed, the deflection of the spring 25 being increased to oppose theincreased fluid pressure and to determine the extent of valveclosingmovement. Upon decrease in speed, the spring 25 overcomes thedecreased fluid pressure and moves the admission valve in openingdirection to increase the motive fluid admission.

The speed setting of the governor is varied by rotating the stem 21 tovary the position of the spring nut 24 on the screw-threaded portion ofthe rod. To increase the speed setting, the spring nut is lowered withrespect to the rod 21. This provides increased compression of the springfor a given position of the admission valve, consequently, a higherspeed is obtained before the fluid pressure balances the force of thespring. To decrease the speed setting, the nut 2a is raised to decreasethe spring compression for a given valve opening.

In the position shown in Fig. 2, it will be noted that the astern valve16 is wide open and that the spring nut 24' is at the lower end of thescrew-threaded portion oi the rod 21', thereby providing maximum speedsetting of the governor 18. The controlling gear 30, mounted on theshaft 31, is at the lower end of its travel and is in mesh with the gear23'.

To reduce the speed setting oi the astern governor 18, the handwheel' 37is turned in counter= clockwise direction. The shaft 31 is turned incounter-clockwise direction, as viewed in Fig. 42, through the shaft 36and the gears so and 35. The gear 23' is rotated by the controlling gearso and turns the rod 21' to raise the position of the spring nut 24thereon. This movement lowers the speed setting, since a decreased fluidpressure is required to balance the force oil the spring 25 at anyposition of the valve 16.

This operation may be continued until zero speed setting is reached,that is the relative position of the nut 24: and the rod 21' at whichthe valve 16 is on its seat and there is no compression oi the spring25'. If the turbine is still rotating due to inertia, the fluid pressuredeveloped merely serves to hold the valve 16 against its seat. At thispoint, the controlling gear so, which has been moved upwardly by thescrew-threads 39, comes into engagement with the gear 23. As shown onthe drawing, the spring nut 24 is at the upper end of the screw-threadedportion of the rod 21 and holds the spring 25 under a slight tension soas to hold the valve 15 firmly on its seat.

The controlling gear to is now in mesh with both of the gear-s23 and23', and upon further movement thereof in the same direction, it rotatesboth of said gears in clockwise direction as seen in Fig. d. Thismovement raises the spring nut 24 of the governor 18 still further,thereby placing the spring 25' under tension. .At the same time, therotation of the rod 21 by the gear 23 lowers the spring nut 24 of thegovernor 17 and releases the tension on the spring 25. This movementcontinues until each of the gears 23 and 23' has made about two turns,at which point the controlling gear 30 disengages the gear 23', leavingthe spring 25' in tension and the governor at this point also, thetension of the spring aesaoes 25 has been released and, upon furtherdownward movement of the nut 2% relative to the rod 21, the speedsetting of the governor 17 is raised from zero speed setting. If theturbine is not rotating and there is no fluid pressure, the valve 15 israised. However. if it is still rotating, the fluid pressure compressesthe spring 25 until the compression equals the force of the fluidpressure. Then, upon further movement, the rod 21 is moved upwardly toopen the admission valve 15. Ordinarily, the speed of the turbine inastern direction will be rapidly reduced, so that the fluid pressurewill be low and an opening movement of the admission valve 15 will berapidly effected.

' If the fluid pressure is zero or relatively low,

a few turns of the gear 23, which may be eimeans of the handwheel 37 tothe other end oi its travel, the mechanism operates in exactly thereverse manner. The speed setting of the governor 1'? is first reducedto zero speed setting; at which point the controlling gear 30 comes intomesh with the gear 23'. The spring 25 is then placed under tension whilethe tension oi" the spring 25' is released, after which the controllinggear 30 disengages the gear 23 and raises the speed setting of thegovernor is. The controlling gear 30 moves downwardly in this operation.

In order that the gears may always come into engagement in the samerelation, the gear teeth which first engage are formed to projectslightly as shown at ii. The projection is 1cm than the pitch of one ofthe screw-threads 39, however, in order to avoid engagement upon thesecond tum of the gear so after disengaging one or the gears 23 and 23'.I

The pitch of the screw-threads 39 bears a ratio to the pitch of thescrew threads 38 which is at least as great as the gear ratio oi thegear 3% to the gear 23, in order to insure that after the gear so hasmoved upwardly into mesh with the gear 23,- it will always be insuficiently raised position.

to remain in engagement therewith.

From the above description, it will be seen that I have provided a valveoperating mechanimi whereby the turbine may be stopped or reversed veryquickly. A relatively small movement of the handwheel 37, such as oneturn thereof, will re= duce the speed setting suficientlv so that thefluid pressure will close the valve tightly, and the speed setting canthen be fully decreased while the turbine is dropping in speed. with inbringing up the speed of the turbine. by rotating the handwheel 37approximately one turn, the speed setting will be increased suficientlyto hring the valve to wide open position, as there is in sumcient fluidpressure to balance the force of the Mil from the spirit thereof, and Idesire, therefore,

that only such limitations shall be placed thereupon as are imposed bythe prior art or as are specifically set forth in the appended claims.

What I claim is:

' 1. The combination with a reversing turbine having an ahead and anastern admission valve,

of a governing mechanism therefor comprising a governor having avariable speed isetting for each admission valve, a movable controllingmemberfand means operable upon movement of said member from one end ofits travel toward the other to decrease the speed setting of onegovernor and to close the admission valve controlled thereby andthereafter to raise the speed setting of the other governor and to openthe admission valve controlled by the latter.

2. The combination with a prime mover having an ahead admission valveand an astem admission valve, of a governing mechanism thereforcomprising a speed-responsive governor for each.

admission valve, and speed controlling mechanism for said governors,said speed controlling mechanism being operative to successively reducethe speed setting of one governor to zero speed and thereafter to raisethe speed setting'of the other associated governor from zero speedsetting, it

moves out of engagement with the other gear, the latter gear thenproviding zero speed setting of its governor.

4. The combination with; a reversing turbine having an ahead and anastem admission valve, of a governing mechanism therefor comprisinggovernors for the respective valves, each governor having speed changermeans including and operated by a gear, and an axially movablecontrolling gear adapted to operate said gears, the relative arrangementof the gears and the movement of the controlling gear being such that ina limited range of movement the controlling gear is in mesh with bothgears and efieots zero speed setting of both governors and upon movementout of said range in either direction moves out of engagement with onegear, leaving its governor at zero speed setting, and moves the othergear to raise the speed'setting of the associated governor above zerospeed setting.

5. The combination with a reversing turbine having an ahead and anastern admission valve, of a governing mechanism therefor comprisinggovernors for the respective valves, each governor having speed changermeans including and operated by a gear, and a controlling gear adaptedto operate said gears, the arrangementof the gears and the movement ofthe controlling gear being such that but one governor at a time may havea speed setting above zero speed setting and that the controlling gearupon movement in'one direction decreases the speed setting of onegovernor to zero speed setting and then raises the setting of the othergovernor from zero speed setting.

6. The combination with a reversing turbine having an ahead and anastern admission valve,

of a governing mechanism therefor comprising 7. The combination with areversing turbine having an ahead and an astern admission valve, of agoverning mechanism therefor comprising means providing fluid pressurevarying as a function of the speed of the turbine, fluid pressuregovernors for the respective valves, each governor comprising acylinder, a piston therein, a rotatable rod connecting the piston to thevalve, a gear fixed on said rod, a spring nut screw-threaded on saidrod, a spring having one end attached to the spring nut and the otherend to a stationary part of the governor, and meansfor admitting saidfluid pressure to the cylinder to bias the piston in valve-closingdirection, and a controlling gear adapted to engage said gears on therods, the spring nut of one governor being moved on its rod so that itsspring biases the valve in closing direction and the spring nut of theother governor being moved on its rod so that its spring biases thevalve in opening direction when the controlling gear is near one end ofits travel and vice-verse when the controlling gear is near the otherend of its travel.

, HENRY F. SCHMIDT.

